A timeline of Sidney Crosby's concussion and recovery

Jan. 1, 2011 — Crosby, the NHL's leading scorer and 11 months removed from leading Canada to the Olympic men's hockey gold medal, is woozy and clearly shaken after being levelled by a blind-side hit from the Capitals' David Steckel late in the second period of the Winter Classic at Heinz Field in Pittsburgh. Despite being badly shaken, Crosby remains in a game that is played in a steady rain.

Jan. 5, 2011 — Because Crosby shows no signs of a concussion following the Steckel hit — he complains only of neck pain — he is cleared to play at home four nights later against Tampa Bay. During the an 8-1 Penguins victory over Tampa Bay, Crosby is driven hard into the boards by Lightning defenceman Victor Hedman.

Jan. 6, 2011 — Crosby flies to Montreal for a Penguins-Canadiens game, only to return to Pittsburgh after experiencing concussion-like symptoms. After being examined by Michael Collins, a concussion specialist at the University of Pittsburgh Medical Center, Crosby is diagnosed with a concussion.

Jan. 7, 2011 — After testing Crosby, Collins determines that the concussion is affecting Crosby's vestibular system, the part of the brain that allows an individual to stand upright and maintain balance. Collins knows then that Crosby will have a lengthy recovery. Neither Collins nor the Penguins comment on this until a press conference on Sept. 7.

March 31, 2011 — After experiencing numerous symptoms from the concussion, including fatigue, fogginess and a sensitivity to light and sound, Crosby stays off the ice for nearly three months before being cleared to resume working out during a Penguins' trip to Tampa Bay.

Mid-April 2011 — Stops practising during Pittsburgh's first-round playoff loss to Tampa Bay when his concussion symptoms, including headaches, return. He does not work out or practice again until the Penguins are eliminated.

May 2011 — Vacations in France while remaining off the ice.

June 2, 2011 — Cleared by the Penguins to resume off-season activities, including skating and conditioning work.

July 15, 2011 — Staying with his conditioning schedule from past summers, Crosby begins strenuous workouts designed to get him ready for training camp in two months.

Aug. 24, 2011 — The Penguins issue a statement saying Crosby has altered his off-season workouts, after he again experiences concussion-related symptoms.

Sept. 7, 2011 — Crosby makes his first public appearance since April at a press conference, saying he has shown rapid improvement over the previous three weeks. The two concussion specialists treating him say he is expected to make a full recovery, with no lingering injury-treated issues or effect on his quality of life. No timeline is given for his return to the NHL.

Sept. 16, 2011 — Penguins scheduled to open training camp. Crosby is not expected to initially take part.

Oct. 6, 2011 — Penguins open the NHL season at Vancouver. Crosby has not been officially ruled out, though it appears unlikely he will be ready to play.